Project description:Class-switching to IgG2a/c in mice is a hallmark response to intracellular pathogens. T cells can promote class-switching and the predominant pathway for induction of IgG2a/c antibody responses has been suggested to be via stimulation from Th1 cells. We previously formulated CAF®01 (cationic liposomes containing dimethyldioctadecylammonium bromide (DDA) and Trehalose-6,6-dibehenate (TDB)) with the lipidated TLR7/8 agonist 3M-052 (DDA/TDB/3M-052), which promoted robust Th1 immunity in newborn mice. When testing this adjuvant in adult mice using the recombinant Chlamydia trachomatis (C.t.) vaccine antigen CTH522, it similarly enhanced IgG2a/c responses compared to DDA/TDB, but surprisingly reduced the magnitude of the IFN-g+ Th1 response in a TLR7 agonist dose-dependent manner. Single cell RNA-sequencing revealed that DDA/TDB/3M-052 liposomes initiated early transcription of class-switch regulating genes directly in pre-germinal center B cells. Mixed bone marrow chimeras further demonstrated that this adjuvant did not require Th1 cells for IgG2a/c switching, but rather facilitated TLR7-dependent T-bet programming directly in B cells. This study underlines that adjuvant-directed IgG2a/c class-switching in vivo can occur in the absence of T cell help, via direct activation of TLR7 on B cells and positions DDA/TDB/3M-052 as a powerful adjuvant capable of eliciting type I-like immunity in B cells without strong induction of Th1 responses.
Project description:This study aimed at integrating metabolomics and proteomics data for a comprehensive view of the molecular targets of intervention of protein extracts from Tenebrio molitor in treating hypertension. Serum samples from spontaneously hypertensive rats and Wistar Kyoto rats were analyzed using a quantitative metabolomics and label-free proteomics approach based on liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS). Among deregulated metabolites and proteins in hypertensive rats, we found 15 metabolites and 17 proteins that were restored by supplementation with Tenebrio molitor protein extract. The combination of metabolomics and proteomics provided useful data to uncover the molecular targets of intervention and the underlying functional mechanism of Tenebrio molitor protein extract in an animal model such as spontaneously hypertensive rats. The results suggested that Tenebrio molitor supplementation could effectively treat hypertension, partially by regulating proteins and molecules mainly involved in biological pathways associated to angiotensinogen-angiotensin, Serin protease inhibitors, kallikrein–kinin, reactive oxygen scavenging, and lipid peroxidation.
Project description:The interplay between pathogens and hosts has been studied for decades using targeted approaches such as the analysis of mutants and host immunological responses. Although much has been learned from such studies, they focus on individual pathways and fail to reveal the global effects of infection on the host. To alleviate this issue, high-throughput methods such as transcriptomics and proteomics have been used to study host-pathogen interactions. Recently, metabolomics was established as a new method to study changes in the biochemical composition of host tissues. We report a metabolomics study of Salmonella enterica serovar Typhimurium infection. We used Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Direct Infusion to reveal that dozens of host metabolic pathways are affected by Salmonella in a murine infection model. In particular, multiple host hormone pathways are disrupted. Our results identify unappreciated effects of infection on host metabolism and shed light on mechanisms used by Salmonella to cause disease, and by the host to counter infection. Female C57BL/6 mice were infected with Salmonella enterica serovar Typhimurium SL1344 cells by oral gavage. Feces and livers were collected and metabolites extracted using acetonitrile. For experiments with feces, samples were collected from 4 mice before and after infection. For liver experiments, 11 uninfected and 11 infected mice were used. Samples were combined into 3 groups of 3-4 mice each, resulting in the analysis of 3 group samples of uninfected and 3 of infected mice. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140 [PMID 19081807]). To identify differences in metabolite composition between uninfected and infected samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from uninfected and infected mice. To assign possible metabolite identities, monoisotopic neutral masses of interest were queried against MassTrix (http://masstrix.org). Masses were searched against the Mus musculus database within a mass error of 3 ppm. Data were analyzed by unpaired t tests with 95% confidence intervals.
Project description:Salinization poses a significant challenge in agriculture, exacerbated by anthropogenic global warming. Biostimulants, derived from living microorganisms or natural extracts, have emerged as valuable tools for conventional and organic agriculture. However, our understanding of the molecular mechanisms underlying the effects of biostimulants is very limited, especially in crops under real cultivation conditions. In this study, we adopted an integrative approach to investigate the effectiveness of the combined application of plant growth-promoting bacterium (Bacillus megaterium strain BM08) and a non-microbial biostimulant under control conditions (normal watering) and salt stress. After confirming the yield increase under both conditions, we investigated the molecular mechanisms underlying the observed effect by measuring a number of physiological parameters (i.e., lipid peroxidation, antioxidants, chlorophylls, total phenolics and phytohormone content), as well as RNA sequencing and primary metabolite analyses. Our findings reveal that the combined effect of the microbial and non-microbial biostimulants led to a decrease in the antioxidant response and an up-regulation of genes involved in cytokinin biosynthesis under salt stress conditions. This, in turn, resulted in a higher concentration of the bioactive cytokinin, isopentenyladenosine, in roots and leaves and an increase in γ-aminobutyric acid, a non-proteic amino acid related to abiotic stress responses. In addition, we observed a decrease in malic acid, along with an abscisic acid (ABA)-independent up-regulation of SR-kinases, a family of protein kinases associated with abiotic stress responses. Furthermore, we observed that the single application of the non-microbial biostimulant triggers an ABA-dependent response under salt stress; however, when combined with the microbial biostimulant, it potentiated the mechanisms triggered by the BM08 bacterial strain. This comprehensive investigation shows that the combination of two biostimulants is able to elicit a cytokinin-dependent response that may explain the observed yield increase under salt stress conditions.